diff --git a/frontend/packages/swarm-ui/src/pages/review-settings/ClassifierSettings.tsx b/frontend/packages/swarm-ui/src/pages/review-settings/ClassifierSettings.tsx
index 475c371a..0d6cfaba 100644
--- a/frontend/packages/swarm-ui/src/pages/review-settings/ClassifierSettings.tsx
+++ b/frontend/packages/swarm-ui/src/pages/review-settings/ClassifierSettings.tsx
@@ -34,10 +34,17 @@ const RUNTIME_OPTIONS = [
   { value: "acp", label: "ACP (opencode)" },
 ];
 
-const EFFORT_OPTIONS = [
-  { value: "", label: "claude's default" },
-  ...EFFORTS.map((e) => ({ value: e, label: e })),
-];
+// The empty effort option is the runtime's own default: claude's on the API
+// key runtime, opencode's on ACP.
+function effortOptions(runtime: Runtime) {
+  return [
+    {
+      value: "",
+      label: runtime === "acp" ? "opencode's default" : "claude's default",
+    },
+    ...EFFORTS.map((e) => ({ value: e, label: e })),
+  ];
+}
 
 export function ClassifierSettings() {
   // The settings as the controller holds them; null until the first read.
@@ -147,7 +154,7 @@ export function ClassifierSettings() {
               id="classifier-effort"
               label="effort"
               value={draft.effort}
-              options={EFFORT_OPTIONS}
+              options={effortOptions(draft.runtime)}
               onChange={(effort) => edit({ ...draft, effort })}
             />
             <TextField
diff --git a/frontend/packages/swarm-ui/src/pages/review-settings/SettingsTypes.ts b/frontend/packages/swarm-ui/src/pages/review-settings/SettingsTypes.ts
index 0e30e61f..58995b7c 100644
--- a/frontend/packages/swarm-ui/src/pages/review-settings/SettingsTypes.ts
+++ b/frontend/packages/swarm-ui/src/pages/review-settings/SettingsTypes.ts
@@ -29,7 +29,8 @@ export interface AcpSettings {
 /** The settings in force. A PUT changes only the fields it carries. */
 export interface ClassifierSettingsBody {
   model: string;
-  /** `null` is claude's own default, which passes no `--effort`. */
+  /** `null` is the runtime's own default: claude's, which passes no
+   * `--effort`, or opencode's. */
   effort: Effort | null;
   max_concurrent_reviews: number;
   runtime: Runtime;
@@ -40,7 +41,7 @@ export interface ClassifierSettingsBody {
 /** The form's fields as the user typed them. */
 export interface SettingsDraft {
   model: string;
-  /** An effort, or `""` for claude's default. */
+  /** An effort, or `""` for the runtime's own default. */
   effort: string;
   max: string;
   runtime: Runtime;